Electrical switches

ABSTRACT

An electrical switch includes a body housing a pair of fixed contacts. A movable contact is movable into and out of engagement with the fixed contacts, and is urged out of engagement with the fixed contacts by a spring. The body of the switches provided with a pair of resilient lugs whereby the switch can be engaged with the casing of a further switch, so that an operating member of the further switch serves also to move the movable contact against the action of said spring.

Patented Ma 16, 1972 swarm i2 Shoots-$110M l INVENTOR Q in 7 r 4 J VAdw 'TTORNEYS Patented May 16, 1972 3,663,778

2 Shoots-Sheet ATTOFPNEYB ELECTRICAL SWITCHES This invention relates to electrical switches.

A switch according to the invention includes a hollow body, a pair'of fixed contacts within the body, a movable contact movable into and out of engagement with the fixed contacts, resilient means urging the movable contact in one direction relative to the fixed contacts and means on the body whereby the body can be releasably engaged with the casing of a further switch so that an operating member carried by the further switch is engageable with said movable contact to move the movable contact against the action of said resilient means.

IN THE ACCOMPANYING DRAWINGS FIG. 1 is a sectional view of a switch in accordance with one example of the invention, shown engaged with an associated device, I

FIG. 2 is a plan view of the base of the device shown in FIG.

FIG. 3 is an end view of the switch shown in FIG. 1, and

FIG. 4 is a side elevational view of part of the switch shown in FIG. 1.

Referring to the drawing, the switch includes a moulded synthetic resin, cup-shaped body 11 including an integral base 12. Centrally disposed in the base. 12 is a cylindrical recess 13 and positioned diametrically opposite one another on opposite sides of the recess 13 are a pair of fixed contacts 14. The fixed contacts 14 are raised from the inner surface of the base 12, and each fixed contact is electrically connected to a respective terminal blade (one of which is shown at 14a) on the exterior surface of the base. Adjacent the end of the body 11 remote from the base 12 the inner wall of the body 11 is undercut to define a shoulder 15 which is presented towards the base 12, and at its end remote from the base 12 the wall of the body 11 is extended to define a pair of diametrically opposite, axially extending legs 16 which include respective, integral outwardly extending lugs 17 at their free ends.

Slidably mounted within the body 11 for movement towards and away from the base 12 is a conductive plate 18, the diameter of which is substantially equal to the internal diameter of the body 11, and greater than the minimum diameter of the shoulder 15. The plate 18 is inserted into the body 11 by deforming the wall of the body 11 to permit the plate 18 to locate behind the shoulder 15, whereafter the movement of the plate 15 is limited in one direction by the fixed contacts on the base 12, and in the other direction by the shoulder 15. Extending between the plate 18 and the base of the recess 13 is a compression spring 19 which urges the plate 18 to contact with the shoulder 15, and secured to the plate 18 at the midpoint of the face of the plate 18 remote from the base 12 is a button 21 formed from insulating material. It will be appreciated that movement of the plate 18 against the action of the spring 19 will cause the plate 18 to abut against the fixed contacts 14, and thereby complete an electrical circuit between the terminal blades 14a.

The legs 16, together with their outwardly extending lugs 17 are used to releasably secure the switch to the casing of a device which includes an operating member 24 capable of engaging the button 21 in a manner to move the plate 18 against the action of the spring 19. In one example of the use of the switch, the switch is associated with a further electrical switch 22, the body 11 being releasably secured to the base portion 23 of the casing of the switch 22. The switch 22 includes an operating spindle 24 which is movable angularly relative to the casing of the switch 22 to operate the contacts of the switch 22. The spindle 24 is movable axially relative tothe casing of the switch 22 against the action of a spring 25, and the arrangement of the switch 22 is such that axial movement of the spindle 24 causes one end, 24a of the spindle to project from the base portion 23 of the casing of the switch. The base 23 is formed with a centrally disposed aperture through which the portion 240 of the spindle extends, and the base 23 is further formed with a pair of arcuate, diametrically opposite slots 26 on opposite sides of the spindle 24. The slots 26 are each formed with an enlarged portion 26a adjacent one end thereof, and in order to secure the body 11 to the switch 22, the legs 16 of the body 11 are inserted through the enlarged portions 26a of the slots 26. The enlarged portions of the slots 26 are so dimensioned that the lugs 17 can pass therethrough, and after insertion of the legs 16 through the enlarged portions of the slots 26 the body 11 is rotated relative to the base 23 so that the legs 16 ride along the arcuate slots 26, away from the enlarged portions of the slots 26, and the lugs 17 engage the surface of the base 23 remote from the body 11. Thus, the body 11 is engaged with the base 23 in the manner of a bayonet connection, the lugs 17 engaging the base 23 to prevent withdrawal of the body 11 from the base 23. The lugs 17 include respective ramp surfaces 28 which, during initial rotation of the body 11 relative to the base 23, engage the inner surface of the base 23 and serve to stress the open end of the body 11 against the outer surface of the base 23, to take up any free play between the body 11 and the base 23 in an axial direction. Moreover, the open end of the body 11 is formed with a pair of diametrically opposite integral latch members, in the form of ramps 29, which, when the body 11 reaches the desired angular position relative to the base 23, enter the slots 26 in the base 23 to resist angular movement of the body 11 relative to the base 23 in a direction to disengage the body 11 from the base 23. The arrangement is such that when the body 11 is engaged with the base 23, then the portion 24a of the spindle 24 is aligned with the button 21, so that upon axial movement of the spindle 24 against the action of the spring 25, the spindle 24 engages the button 21 and moves the plate 18 against the action of the spring 19 to complete the circuit between the fixed contacts 14. Upon release of the spindle 24 the parts of the two switches are returned to the position shown in the drawing by the springs 25 and 19.

Since the spindle 24 is axially aligned with the button 21, then axial movement of the spindle 24 will engage the button 21 regardless of the angular position of the spindle 24.

In one example of the use of the construction shown in the drawings, the contacts of the switch 22, operated by angular movement of the spindle 24, control the operation of the windscreen wiper unit of a road vehicle, and the contacts 14 are connected in the windscreen washer circuit of the vehicle so that axial movement of the spindle 24 completes the windscreen washer circuit of the vehicle to operate the windscreen washers.

Having thus described my invention what I claim as new and desire to secure by Letters Patent is:

1. An electrical switch including a hollow body having an open end, a pair of fixed contacts within the body, a movable contact movable into and out of engagement with the fixed contacts, resilient means urging the movable contact towards said open end of the body, an internal shoulder on said body against which said movable contact is urged, so that said shoulder retains said movable contact within said body, and means on the body whereby the body can be releasably engaged with a casing of a further switch so that an operating member carried by the further switch is engageable with said movable contact through said open end of the body to move the movable contact against the action of said resilient means.

2. A switch as claimed in claim 1 wherein said means includes a pair of legs integral with the body and arranged to be engaged in the manner of a bayonet connection with said further switch.

3. A switch assembly comprising in combination a switch as claimed in claim 1 and a further switch, the operating member of said further switch being movable angularly to operate contacts of the further switch and being movable axially to move said movable contact.

4. A switch assembly comprising in combination a switch as claimed in claim 2 and a further switch, the operating member of said further switch being movable angularly to operate contacts of said further switch and being movable axially to move said movable contact, said legs being received in respective apertures in a base of said further switch and including lugs which engage the surface of said base remote from the first mentioned switch to retain the first mentioned switch engaged with the further switch.

5. A switch assembly comprising in combination a first switch having a casing closed at one end by a base, an operating member, means mounting said operating member for longitudinal movement towards and away from said base, and further mounting said operating member for angular movement relative to said casing, electrical switch contacts, means coupling said switch contacts and said operating member so that said switch contacts are operated in response to angular movement of said operating member relative to said casing, a second switch, including a hollow body open at one end, a pair of fixed electrical contacts within the hollow body, a movable contact movable within the hollow body towards and away from the fixed contacts, resilient means urging said body away from said fixed contacts, an internal shoulder within the body against which said movable contact is urged by said resilient means, said internal shoulder limiting movement of said movable contact towards said open end of the body, and, bayonet connection means on said body, and said base of said first switch coupling said body to said base, so that said open end of said body is presented to said base, said base having therein an aperture through which said operating member can pass during longitudinal movement thereof, so that longitudinal movement of said operating member moves said movable contact relative to said fixed contacts. 

1. An electrical switch including a hollow body having an open end, a pair of fixed contacts within the body, a movable conTact movable into and out of engagement with the fixed contacts, resilient means urging the movable contact towards said open end of the body, an internal shoulder on said body against which said movable contact is urged, so that said shoulder retains said movable contact within said body, and means on the body whereby the body can be releasably engaged with a casing of a further switch so that an operating member carried by the further switch is engageable with said movable contact through said open end of the body to move the movable contact against the action of said resilient means.
 2. A switch as claimed in claim 1 wherein said means includes a pair of legs integral with the body and arranged to be engaged in the manner of a bayonet connection with said further switch.
 3. A switch assembly comprising in combination a switch as claimed in claim 1 and a further switch, the operating member of said further switch being movable angularly to operate contacts of the further switch and being movable axially to move said movable contact.
 4. A switch assembly comprising in combination a switch as claimed in claim 2 and a further switch, the operating member of said further switch being movable angularly to operate contacts of said further switch and being movable axially to move said movable contact, said legs being received in respective apertures in a base of said further switch and including lugs which engage the surface of said base remote from the first mentioned switch to retain the first mentioned switch engaged with the further switch.
 5. A switch assembly comprising in combination a first switch having a casing closed at one end by a base, an operating member, means mounting said operating member for longitudinal movement towards and away from said base, and further mounting said operating member for angular movement relative to said casing, electrical switch contacts, means coupling said switch contacts and said operating member so that said switch contacts are operated in response to angular movement of said operating member relative to said casing, a second switch, including a hollow body open at one end, a pair of fixed electrical contacts within the hollow body, a movable contact movable within the hollow body towards and away from the fixed contacts, resilient means urging said body away from said fixed contacts, an internal shoulder within the body against which said movable contact is urged by said resilient means, said internal shoulder limiting movement of said movable contact towards said open end of the body, and, bayonet connection means on said body, and said base of said first switch coupling said body to said base, so that said open end of said body is presented to said base, said base having therein an aperture through which said operating member can pass during longitudinal movement thereof, so that longitudinal movement of said operating member moves said movable contact relative to said fixed contacts. 